Weather controlled lighting fixture



July 19, 1966 1. GOODBAR WEATHER CONTROLLED LIGHTING FIXTURE Filed Nov. 15, 1963 [FIGI United States Patent 3,261,974 WEATHER CONTROLLED LIGHTING FIXTURE Isaac Goodbar, New York, N.Y. (93-02 211th St., Queens Village 28, N.Y.) Filed Nov. 15, 1963, Ser. No. 324,096 4 Claims. (Cl. 240-25) The invention relates to lighting fixtures for streets, thruways and other types of highways or roadways.

The reflecting characteristics from a dry pavement are very different from those of the same pavement when wet. When the pavement is dry, the best lighting fixture would be one in which the luminous source is shielded in such a way that drivers of approaching vehicles can see neither the luminous source itself nor any light rays reflected directly from the shield. However, when the pavement is wet, such a fixture would not be at all satisfactory. In this case pavement reflections become specular, and if the light emitted by the fixture is restricted as I have described, the light images reflected on the wet pavement would be seen only after approaching vehicles have come within the immediate environs of the lighting fixture. Hence obstacles on the road will be seen against a dark background and their visibility will then be very poor, with inadequate discernment by silhouette. The importance of discernment by silhouette is well understood in the art to which the present invention appertains and is recognized, for example, in Fundamentals of Rural Highway Lighting, Sweet, Transactions of the Illuminating Engineering Society, May 1936. This problem of illumination of roadways in bad weather has led to the general adoption of fixtures emitting light up to and even above the horizontal. Such fixtures are seen reflected on the wet pavement and show the road brightly outlined for a great distance ahead of the driver. However, it will be appreciated that such fixtures also shine directly into the eyes of drivers and, being angularly very near the lines of vision, produce undesirable glare.

SUMMARY The object of my invention is to provide an improved form of lighting fixture which will do a better job of meeting the requirements for proper lighting of both wet and dry pavements, and which therefore will be less of a compromise between fixtures which would be best just for one condition or the other.

According to my invention there is provided a lighting fixture comprising a shielding, or shielding and reflecting, element having an effective shielding angle which obscures the luminous source from the view of drivers of oncoming vehicles, and a receptacle or container for liquid extending below such shielding element and disposed to receive and accumulate rain water or other forms of precipitation. This receptacle has light-transmitting walls, e.g. walls made of transparent glass or plastic material, forming a reservoir for water so accumulated. These light transmitting walls are shaped as prisms to deflect the light upwards or downwards at angles far from the horizontal when the receptacle is empty. When the receptacle is filled with water, having a refractive index much closer to the one of the transparent walls than air does, the abovementioned prisms practically disappear and the light is emitted at angles above the range of the aforesaid shielding angle. The receptacle may be constituted by a trough extending along the lower edge of the reflecting element to receive the run-off from the upper surfaces of the fixture for rapid build-up of the temporary water prism.

In this manner I provide what might be described as a Weather-controlled lighting fixture having one kind of lighting characteristics when the pavement is dry and another kind of lighting characteristics when it is raining or 3,261,974 Patented July 19, I966 snowing and the pavement is wet. This makes it possible to design the fixture to more nearly ideal performance under the different weather conditions. Furthermore, the fixture has the advantage as it will be explained of not revealing, when empty, any dirt that may accumulate in the receptacle.

DESCRIPTION With reference to the accompanying drawings, I shall now describe one of the best modes contemplated by me for carrying out my invention, other such modes were described by me in the copending applications Serial No. 62,187, filed October 12, 1960 and Serial No. 279,526, filed May 10, 1963, now U.S. Patent Nos. 3,130,923 and 3,169,709.

FIG. 1 is a schematic View to illustrate the relationship between the normal shielding angle of the top of an automobile and the effective shielding angle of a fixture embodying my invention.

FIG. 2 is a vertical transverse sectional view of my improved fixture.

FIG. 3 is an enlarged detail view taken as indicated at 3--3 in FIG. 2.

FIG. 4 shows one of the many possible variations of the receptacle 9 of FIG. '2.

It is possible as described in U.S. Patent 3,098,612 to construct a light fixture which when viewed from positions exceeding a given angle to a vertical plane containing the luminous source will appear very low in the scale of brightness. When such a fixture is used for lighting roadways and the like, it is possible to select an effective shielding angle which when properly related to the shielding angle of the top of an automobile will have the result of obscuring the entire luminous source from the vision of the driver. Under these conditions direct glare from the luminous source and from its reflecting shield would be eliminated. This condition is illustrated in FIG. 1, wherein angle s represents the angle below the horizontal of the highest light rays projected from the luminous source below the nearest edge of the reflecting shield of the fixture, and s is the angle above the horizontal of the highest line of vision of the driver below the shield afforded by the top of the automobile. When s equals s, it will be impossible for the driver to see the luminous source at any time because at the very moment that the forward progress of his car would begin to reveal the luminous source to him, the shield afforded by the top of his car will cut off his view. By making s somewhat greater than s, a similar result is achieved and the angle s preferably is selected so as to be accommodated to the minimum shielding afforded by any standard make automobile when driven from the lowest drivers seat position by a person of average height. Even in the absence of any shielding afforded by the top or visor of an automobile, my improved fixture will reduce glare and can entirely eliminate direct glare from all but the nearest fixture or fixtures, with reduced glare from the latter. Similarly, the fixture will be designed so that-the farther portion of its reflecting shield will project no direct or indirect image of the luminous source at an angle c from the vertical plane containing the luminous source that is greater than min-us s. Otherwise stated, angle c will be no greater than angle s Referring now to FIG. 2, I shall describe the preferred construction of my arrangement for altering the optical distribution of the light according to the condition of the weather. In dry weather all of the light will be confined below angle s so that all glare will be avoided. When it is raining, or when it is snowing under temperature conditions which result in a wet roadway, the accumulation of water in certain parts of the fixture will change the distribution so that light will be emitted up to the horizontal or even higher. This will make the road well visible for a requisite distance ahead and make possible a satisfactory discernment by silhouette of obstacles in the drivers path.

Still referring to FIG. 2, my lighting fixture comprises a reflecting element or shield 4 having an effective shielding angle which obscures the luminous source 5 from the view of drivers of oncoming vehicles. By effective shielding angle I refer to the angle s, this angle being determined by a line drawn through the lowest point 6 of the nearest edge of shield 4 to a point of tangency 7 at the lower end of the luminous source 5, angle s then being the angle which such line makes with the horizontal. The defined expression also implies that angle will not be greater than 90 minus s, so that direct reflections of the luminous source from a point such as 8 in the reflecting shield will not be visible above the line 6, 7. My fixture comprises further a receptacle, or receptacles, 9 extending below reflecting shield element 4 disposed to receive and accumulate precipitation and having light-transmitting walls 10, 11 in the shape of prisms as shown in FIG. 2 forming a reservoir for water so accumulated. These walls may be of transparent glass or plastic.

An opaque shield 15 (or black paint) is shown in FIG. 2 to prevent vision of the lower part of receptacle 9.

When the pavement is dry the light rays from the source such as 12, that reach the side 11' of the prism 11 are refracted into 12' and then totally reflected on the opposite face 11", emerging into the atmosphere in an upwards direction, as 12", as is shown on the right side of FIG. 2. This same side of FIG. 2 shows also a visual 13 from a large distance, reaching the face of prism 10. This visual enters the prism, as shown and is also totally reflected upwards into the dark sky, as 13'.

Therefore, when the receptacle 9 is empty no light ray from the source 5 can be emitted at an angle smaller than s below the horizontal and no visual at an angle smaller than s can reach any bright part of the fixture. All glare is accordingly eliminated.

The left side of FIG. 2 shows the receptacle 9 full of water. Since the index of refraction of water is not so different from the one of the prisms 10 and 11 as the one of air was, total reflection no longer takes place on surfaces 10 and 11". Instead, only slight refraction occurs in these surfaces and light rays from the source 5, such as 14, are emitted upwardly above the range of shielding angle s up to and even above the horizontal, as shown (14) Visuals such as 14' now reach the light source 5.

As previously explained, this light near the horizontal will make the specular road well visible for a requisite distance ahead and will make possible satisfactory discernment by silhouette, of obstacles in the dnivers path. Undulations on the face 10 or on a separate spread lens, as shown in FIG. 3, may help spread the light both vertically and horizontally into the desirable zones.

The trough 9 being in contact with the reflecting shield 4 which extends into close proximity with the luminous source 5 transfers a certain amount of heat from the luminous source to the reservoir and the water contained therein, aiding in evaporation of the water after precipitation has stopped.

If desired the reservoir 8 may be provided with means such as apertures in the ends of the trough for draining off the accumulated water at a predetermined rate to the end that the water prism will disappear by the time the roadway dries.

The invention is applicable to fixtures of differing shapes, elongated, circular and other forms, the form chosen for illustration being one which has a reflecting shield of inverted channel form with troughs extending along the lower edges of such shield, the troughs having light-transmitting walls as has been described.

For simplicity the fixture selected to illustrate the invention in its preferred form is designed to control the shielding angle only lengthwise along the roadway. Similar shielding surfaces and troughs may be arranged at the ends of the fixture to control the shielding angle transversely of the roadway. Only in fixtures to be located over intersections this double control may be necessary, otherwise the distribution of light across the roadway does not need to change with the weather.

Other dispositions of the prisms and receptacles may be possible without departing from the scope of the present invention.

Actually the objective of changing the light distribution with the weather so as to avoid glare in dry weather and allow good silhouette perception when it rains can be accomplished with a single prism such as 10 or 11. However, during dry weather a single prism will show, to drivers, the dirt accumulated in some of its faces. Furthermore, this dirt, being strongly lit by the powerful source 5 will be bright and when seen against the dark background may become glaring.

This effect is less noticeable if the inside prism 11 is the one eliminated i.e. the device works almost as well with just prism 10 and this is another possible construction within the scope of the present invention. With this construction within the sides of the element 11 will be 11 and 11" (shown in dotted lines in FIG. 2).

However, the device shown in solid lines hides the dirt better as will be explained.

If dirt is accumulated on surfaces 10" and this dirt is in intimate contact with surface 10", a visual such as 14' will not be totally reflected in its entirety but will be partially reflected, reaching also surfaces 9' and L1" or 11". If these two surfaces are kept in darkness nothing will be seen.

If surface 11" is dirty also it will spread part of the light reaching it from the source 5. The quantity of light dispersed by the dirt on 11" that may reach the dirt on 10" is so small that, with the construction shown in solid lines in FIG. 2 it will be impossible to see any dirt on any of the surfaces when receptacle 9 is empty. With the construction shown in dotted lines, i.e. with only prism 10, if surfaces 9 and 11" are dirty, some more light, dispersed by them, will reach the dirt on 10".

The prisms 10 and 11 could be oriented so as to reflect the visuals 14 and/or the light rays 14 downwards towards the pavement. The results obtained would be almost identical and with prism 1.1 reversed a slightly higher luminous eificiency would be attained since more light would reach the roadway. However, the face of prism 11 emitting the light would be downwards and would then be visible at angles below s and, if it should become dirty, the dirt would show at high brightness.

For this reason the construction shown in FIG. 2 or its equivalent shown in FIG. 4 was considered preferable for the description of the present invention. In FIG. 4, faces 11" and 10" are broken into small steps with a resultant saving in transparent material. The operation is as was described.

During rain the effect of any dirt accumulated on any of the surfaces 10', 10", 9, 11", or 11 and not washed away by the rain will simply be a reduction of the apparent brightness of the source 5, as seen from large distances. Since the brightness of the source 5 is normally very high a considerable reduction may be quite acceptable before cleaning becomes necessary.

The terms and descriptions which I have employed are used in a descriptive and not a limiting sense and I have no intention of excluding such equivalents of the invention described as fall within the scope of the claims.

I claim:

1. A lighting fixture for roadways and the like comprising a shielding element open at the bottom thereof to project light downwardly, a lamp, means for mounting said lamp within said element in a position located above a lower edge of said shielding element to produce an effective shielding angle which in clear weather normally obscures the lamp from the view of drivers of oncoming vehicles, and a receptacle supported by said element extending along and below said lower edge of the shielding element, said receptacle having light transmitting walls disposed to receive and accumulate precipitation, said light transmitting walls including a prismatic wall extending vertically below the lower edge of said shielding element and another wall etxending outwardly and upwardly from the bottom of the reservoir to form a trough, said prismatic wall sides being at such angles that light entering a first side is refracted to contact the second side where it is reflected upwardly.

2. A lighting fixture according to claim 1 in which at least one of the sides of said walls is replaced by steps composed of flat segments parallel to two directions, one of which is the side of said trough.

3. A lighting fixture for roadways and the like comprising a shielding element open at the bottom thereof to project light downwardly, a lamp, means for mounting said lamp within said element in a position located above a lower edge of said shielding element to produce an elfective shielding angle which in clear weather normally go obscures the lamp from the view of drivers of oncoming vehicles, and a receptacle supported by said element extending along and below said lower edge of the shielding element, said receptacle having light transmitting wal-ls disposed to receive and accumulate precipitation, said light transmitting walls including a prismatic wall extending vertically below the lower edge of said shielding element and another wall extending outwardly and upwardly from the bottom of the reservoir to form a trough which widens toward the bottom, said prismatic wall sides being at such angles that light entering a first side is refracted to contact the second side where it is reflected upwardly.

4. A lighting fixture according to claim 3 in which at least one of the sides of said walls is replaced by steps composed of flat segments parallel to two directions, one of which is the side of said trough.

References Cited by the Examiner UNITED STATES PATENTS 3,130,923 4/1964 Goodbar 240-25 NORTON ANSHER, Primary Examiner.

C. R. RHODES, Assistant Examiner. 

1. A LIGHTING FIXTURE FOR ROADWAYS AND THE LIKE COMPRISING A SHIELDING ELEMENT OPEN AT THE BOTTOM THEREOF TO PROJECT LIGHT DOWNWARDLY, A LAMP, MEANS FOR MOUNTING SAID LAMP WITHIN SAID ELEMENT IN A PORTION LOCATED ABOVE A LOWER EDGE OF SAID SHIELDING ELEMENT TO PRODUCE AN EFFECTIVE SHIELDING ANGLE WHICH IN CLEAR WEATHER NORMALLY OBSCURES THE LAMP FROM THE VIEW OF DRIVERS OF ONCOMING VEHICLES, AND RECEPTACLE SUPPORTED BY SAID ELEMENT EXTENDING ALONG AND BELOW SAID LOWER EDGE OF THE SHIELDING ELEMENT, SAID RECEPTACLE HAVING LIGHT TRANSMITTING WALLS DISPOSED TO RECEIVE AND ACCUMULATE PRECIPITATION, SAID LIGHT TRANSMITTING WALLS INCLUDING A PRISMATIC WALL EXTENDING VERTICALLY BELOW THE LOWER EDGE OF SAID SHIELDING ELEMENT AND ANOTHER WALL EXTENDING OUTWARDLY AND UPWARDLY FROM THE BOTTOM OF THE RESERVOIR TO FORM A TROUGH, SAID PRISMATIC WALL SIDES BEING AT SUCH ANGLES THAT LIGHT ENTERING A FIRST SIDE REFRACTED TO CONTACT THE SECOND SIDE WHERE IT IS REFLECTED UPWARDLY. 